.px2rem(@name, @px){
    @{name}: @px / 75 * 1rem;
}
*{
    padding: 0;
    margin: 0;
    list-style: none;
    font-family: "微软雅黑";
}
body,html{
    width: 100%;
    height: 100%;
    background: #ffffff;
}
.tan{display: flex;}
.pl(@w) {
    .px2rem(padding-left,@w)
}
.pr(@w) {
    .px2rem(padding-right,@w)
}
.pt(@w) {
    .px2rem(padding-top,@w)
}
.mt(@w) {
    .px2rem(margin-top,@w)
}
header{
    .px2rem(height,98);
    background: #d30000;
    color: white;
    .px2rem(font-size,50);
    .tan();
    align-items: center;
    justify-content: center;
}
nav{
    width: 90%;
    .px2rem(height,290);
    border: 2px solid #ebebeb;
    border-radius:10px;
    position: absolute;
    top:80px;
    left: 19px;
    background: #ffffff;
    ul li{
        .px2rem(height,98);
        border-bottom:2px solid #e4e4e4 ;
        .tan();
        align-items: center;
        justify-content: space-between;
        span:nth-child(1){
            .pl(20);
        }
        span:nth-child(2){
            .pr(20);
        }
        span{
            display: block;
        }
    }
    li:nth-child(3){
        border-bottom: none;
    }
    li span{
        color: #333333;
        font-size: 20px;
    }
}
.nav_a{
    width: 90%;
    .px2rem(height,290);
    border: 2px solid #ebebeb;
    border-radius:10px;
    position: absolute;
    top:290px;
    left: 19px;
    background: #ffffff;
    ul li{
        .px2rem(height,98);
        border-bottom:2px solid #e4e4e4 ;
        .tan();
        align-items: center;
        justify-content: space-between;
        span:nth-child(1){
            .pl(20);
        }
        span:nth-child(2){
            .pr(20);
        }
        span{
            display: block;
        }
    }
    li:nth-child(3){
        border-bottom: none;
    }
    li span{
        color: #333333;
        font-size: 20px;
    }
}
.nav_b{
    width: 90%;
    .px2rem(height,290);
    border: 2px solid #ebebeb;
    border-radius:10px;
    position: absolute;
    top:500px;
    left: 19px;
    background: #ffffff;
    ul li{
        .px2rem(height,98);
        border-bottom:2px solid #e4e4e4 ;
        .tan();
        align-items: center;
        justify-content: space-between;
        span:nth-child(1){
            .pl(20);
        }
        span:nth-child(2){
            .pr(20);
        }
        span{
            display: block;
        }
    }
    li:nth-child(3){
        border-bottom: none;
    }
    li span{
        color: #333333;
        font-size: 20px;
    }
}